How much does road dust affect crops?

To answer the dust question definitively, a controlled experiment would need to be designed. Such a study would assure that all potential factors possibly affecting plant yields are controlled or held constant. After that, various levels of dust would be applied uniformly to plant leaves and the resulting yield changes carefully measured.

Last week, I spoke at crop days in Regent and Taylor on the impact of the state’s growing oil industry on production agriculture. After making my presentation, discussion turned to a concern about the dust being created by all the increased truck traffic on gravel roads and its effects on crops nearby.

Several producers felt they were observing increasing plant stress and lower yields adjacent to high traffic oil roads. Road dust could have several detrimental effects on plant health. First, the layer of dust on plant leaves could result in plant shading, which would lower photosynthesis.

Second, trace elements in the dust may be toxic to plant biological processes. Third, large quantities of dust on the soil’s surface may draw subsoil moisture. This would leave less water available for plant growth.

After this discussion, someone mentioned that a study should be initiated to quantitatively measure the effects of road dust. The person remarked that many farmers now have yield monitors and easily could measure yields per acre at various distances (30, 60, 90 feet) from a nearby road to see if any yield loss patterns emerged. Farmers who hire custom combiners already might have this information because custom harvesters typically have yield monitors.

Any producers willing to share this information can forward their yield data to me. I will combine all of the responses received and publish a summary in a future column.

Will data from a yield monitor actually settle the dust question?

Unfortunately, yield monitor data probably won’t because so many other environmental and managerial changes affect yields. For example, most farmers realize that headlands or end rows usually don’t receive the same treatment or level of inputs applied relative to the rest of the field. When large farm equipment turns, some product skips occur, but double applications happen elsewhere in the field. Most fields are tilled at an angle, but end rows are tilled at other patterns. Finally, a producer interested in the dust question may be extra attentive when combining the rows in question, which would affect the results.

No one mentioned that road dust actually may lead to increased plant yields. A credible scientific study considers all possible outcomes. Could it be that road dust shades the plants during hot summer days? Perhaps the plant needs some of the micronutrients contained in the dust. Scientists need to be open-minded and consider all outcomes.

To answer the dust question definitively, a controlled experiment would need to be designed. Such a study would assure that all potential factors possibly affecting plant yields are controlled or held constant. After that, various levels of dust would be applied uniformly to plant leaves and the resulting yield changes carefully measured.

It appears that dust will continue building on growing crops before a definitive answer on yield is found.